Synthesis of alpha- and beta-globulins in normal and liverless dog

¹ Surgical and Radioisotope Services, Veterans Administration Research Hospital and Northwestern University Medical School, and Department of Biological Chemistry, University of Illinois College of Medicine, Chicago, Illinois

Incorporation of dl-S³⁵ methionine into electrophoretically separated ₁-, ₂-, and ß-globulins was studied in the same four dogs before and after total hepatectomy. In the normal animal methionine was incorporated rapidly into both - and ß-globulins. Peak specific activity was attained in all fractions at approximately 6–12 hr. The ₁- and ₂-globulins had approximately equal specific activity, expressed as counts per minute per milligram of each fraction, whereas the activity of ß-globulins was about one-half that of either -globulins. Hepatectomy markedly reduced the formation of labeled ₁- and ₂-globulins to only 10% and 25% of the prehepatectomy levels, respectively. Incorporation of methionine into the ß-globulins was not reduced so extensively by hepatectomy, falling only to one-half of normal levels. These observations lead to the conclusion that most (75–90%) of the -globulins are produced by the liver but that only about 50% of the ß-globulins are of hepatic origin.